A four-year-old Russian boy who was found unaccompanied in the Iraqi city of Mosul last month has been reunited with his family in Chechnya, Chechen authorities said in a statement on Thursday.

Bilal Tagirov arrived on a plane coming from the Jordanian capital Amman after Chechnya's leader sent officials to Iraq to retrieve the boy from the former bastion of the Islamic State group.

A video of Tagirov wandering alone through the flashpoint city was widely shared on social media last month, triggering efforts to rescue him.

"I can't say at the moment how I feel, of course I'm happy, I don't even know how to express my gratitude, because I didn't think that I would see this day and that it would come so soon," Bilal's mother Zalikha Ashakhanova told reporters.